What visual cue commonly indicates a drowning swimmer?

A common visual cue that indicates a drowning swimmer is someone bobbing or playing under the water. This behavior often suggests that the person is struggling, as they may not have the strength to keep their head above the surface. Drowning individuals typically cannot call out for help or wave their arms effectively due to the instinctive responses of panic and the body's natural reaction to distress.

This scenario highlights the subtlety of drowning, which can be mistaken for playful behavior. Unlike a swimmer waving for help, which shows an intentional attempt to draw attention, someone who is bobbing beneath the water is often in a silent struggle. Therefore, recognizing this behavior as a potential sign of drowning is crucial for effective rescue efforts.